Year	Percent
1991	29.507
1992	28.815
1993	28.35
1994	27.94
1995	27.898
1996	27.842
1997	27.358
1998	27.147
1999	27.208
2000	27.147
2001	28.943
2002	32.062
2003	29.978
2004	28.692
2005	28.842
2006	29.971
2007	30.07
2008	29.349
2009	29.409
2010	28.627
2011	28.191
2012	27.22
2013	27.412
2014	26.879
2015	27.417
2016	27.942
2017	27.937
2018	27.879
2019	27.822
2020	27.765
2021	27.701
2022	27.637